The invention relates to a method for treating the edges of a sawtooth wire for the card clothing of rollers and carding flats in textile machines.
Sawtooth wires are mainly used as clothing in carding machines, scribbler cards, random cards, openers and cleaning devices, centrifugal cards, opening rollers for open-end spinning machines, opening rollers for friction spinning frames, as well as in stationary carding flats, distributing devices and smoothing devices.
In such kind of apparatusses, the treated fibre material must be transferred from a feeder or roller to the next treatment station and must be treated in a distinct way. To achieve this, it is extremely important that the sawtooth wire clothing is adapted to release the fibre material rapidly and completely and to avoid that fibres adhere to the clothing wire. This applies particularly to opening rollers for open-end spinning machines and friction spinning frames as well as for rollers in random cards and centrifugal cards.
It has been found that the aforementioned objects may be achieved by rounding off the edges of the sawtooth wire clothing, particularly in the region of the front faces of the teeth.
According to a well-known method, a sawtooth wire having punched-out teeth is sand-blasted so as to round the sharp edges of the teeth. It has, however, been found that this kind of treatment of the sawtooth wire leads to a rough surface of the teeth, so that fibres tend to adhere to the same and to clodge the clothing. Also, the points or tips of the teeth are excessively rounded, resulting in an impairment of the carding efficiency of the teeth.